The processing of a wide variety of products involves passing them through processing facilities where they are required to dwell for a predetermined length of time during which such processing is carried out. Such processing facilities may be used for processing a wide variety of products including both food products and non-food products and including both meat products and other products, which may be processed prior to distribution and/or consumption.
The design of such processing facilities must take into account a variety of different requirements. In the first place, there is the dwell time, which is required for the complete processing of the product in the facility. Then there is the requirement for the maintaining of stable processing conditions within the processing facility, and throughout all areas of the processing facility. There is also the requirement for the easy maintenance and in particular the easy cleaning of such facilities after usage, to maintain them in a sterile condition.
Finally, there is the question of the cost of such facilities. One of the principal costs of such facilities is the total floor space occupied by the facilities. Clearly, facilities occupying a greater floor space, will occupy more real estate and thus increase the capital cost, than facilities which can be housed in a smaller space.
This factor will in many cases be dependant upon the volume of product which is required to be processed through the facilities during any given time, and the manner in which such product is to be conveyed into and removed from such processing facilities.
In the latter case, the designer is faced with two basic choices. Either on the one hand the products can simple be physically placed in a chamber, with the doors then being closed, and the product remains in the chamber for a predetermined dwell time, after which it is removed. This system is essentially similar to the cooking of products in a domestic oven, for example. Variations on this process have involved the stacking of products on large multiple product supports. The multiple product supports are then moved in step wise fashion through the processing facility or chamber, in a start/stop fashion.
However, where very large volumes of product are required to be processed on a more or less continuous basis, it is considered desirable to provide for a continuously moving conveyor system conveying the product continuously through the processing facilities or chamber. This greatly facilitates the operation of the preparation of the product prior to entry into the processing facility, and the removal of the product for packaging and the like after exiting from the processing facility The fact that the processing facility has continuously moving conveyor means, ensures that the equipment both upstream and downstream of the processing means can be operated continuously, and in timed synchronized relation to the operation of the conveyor, thus maximizing the efficiency of the entire operation.
In order to provide for a continuously operating conveyor, various considerations must be taken into account, namely the cross-sectional area of the chamber through which the products are being conveyed, which controls the actual volume of product per lineal foot of space, the dwell time or processing time required for any particular type of product, the number of different processing steps, requiring different processing conditions, along the length of the conveyor, to name only some of the considerations. Naturally, where the products must be processed in large volumes then either the speed of the conveyor will have to be relatively slow, or else the length of the chamber through which the product is conveyed will be excessively long. Alternatively, the chamber can have a larger cross-section so that it will handle a larger volume of products per lineal foot, but in this case special conveyor facilities will have to be provided for conveying the product through such a larger chamber. One approach which has been successfully used in the past is to provide an elongated processing chamber, laid out with a series S bends, so that the chamber is of generally sinusoidal shape in plan. A single rail conveyor runs throughout the length of the chamber, carrying product through the chamber. In this way it is possible to arrange for a chamber of considerable length, in a reasonably compact area.
However, one of the problems in this type of solution is the fact that the construction of the single rail conveyor means that the product must be carefully balanced on both sides of the single rail. The problem of sterilizing the conveyor after it has been used is also somewhat troublesome. In addition, where the S bends are located in the chambers, it is more difficult to maintain completely stable processing conditions, so that the processing conditions in some cases may vary from one side of the S to the other.
In addition, it is necessary to provide processing condition facilities such as fans, heaters, humidifiers, smoke generators, and the like and/or water spray or water deluge facilities, at various locations along the length of the conveyor, so as to maintain stable processing conditions along any given length or zone of the conveyor.
It is in fact known that it is less troublesome to maintain stable processing conditions within a processing chamber which has a larger cross-section or dimension, and is somewhat shorter in length.
In the past however, it has been generally considered that such large chambers of this type were not suitable for use with a continuously moving conveyor systems, but on the contrary, were suitable only for batch type start/stop conveyor systems.
In the particular case of processing food products, these considerations become increasingly acute. In food processing operations, standards and requirements for cleanliness and sterility increase from year to year. Accordingly, standards now require that the conveyor and the supports upon which the food products are supported on the conveyor, shall be thoroughly cleaned and sterilized once during each cycle of operation. Clearly this cleansing operation can take place only after the complete processing of a particular product has taken place and prior to loading with fresh product. Accordingly, it is now well understood that it is necessary to provide in such food processing facilities, cleansing and sterilizing facilities which are located between the unloading point, where fully processed product is unloaded, and the loading point where unprocessed product is loaded. When it is considered that the entire convey or system and the supports for the product, are moving continuously throughout, in order to gain the main advantages described above, it will be appreciated that the design of such a cleansing facility in a continuous line presents a number of problems including the further lengthening of the line.
Still another factor of importance in the design of such processing facilities particularly when processing food products such as meat, is that the processing usually involves a cooking step with or without smoking and other steps, followed eventually by a chilling step or process.
Particularly in the cooking stage and the chilling stage it is generally considered to be the preferred practice in the trade to progressively bring the products from their existing, i.e. room temperature, up to the cooking temperature over a period of time, and then to progressively chill the products from the cooking temperature down to an adequate degree of chilling for the purposes intended.
In order to do this, using the previously mentioned elongated processing chamber laid out with S bends, it was necessary to provide a large number of different controls for different zones of the chamber, and it was necessary that they all be carefully monitored and regulated so as to ensure that the right processing conditions were maintained in the right regions or zones of the chamber at all times.
Clearly, it is desirable to provide a processing facility for products, and particularly for meat or food products which is of compact space saving design, and which at the same time overcomes the various problems both of adequate production capacity process control at various stages of the processing, and washing and sterilization facilities.